Err... I think Ryunohige may actually beat Ukon in a lot of situations. Even Conqueror may beat Ukon sometimes (pretty much the ultimate zerg weapon). Right now DD mythics for many jobs are very underrated compared to their damage potential. Not that it matters, because they're made of unobtainium.
The biggest problem for them is how precisely you need to time AM3 activation (AM3 doesn't overwrite AM3), which tends to leave you either without AM3 while trying to build TP to 300, or overTPing at 300TP. Ryunohige has it nice here, because of Spirit/Soul Jump (5x normal hit x~1.7 attacks/round = 170TP average), Meditate (60TP), and AM3 duration all approximately lining up timer-wise, which gives you a little wiggle room and lets you boost your TP as needed. Jump/High Jump recast merits let you just save the Spirit/Soul for after WS if you don't need their TP. They take a lot more effort to play than, say, Ukon though.
Tbqh, I'd definitely get one just because they sound fun to play. The real limitation for me is the 100k Ampuoles, non-spawning Beast Kings, and last 50k tokens I'm missing, though. I feel that I could make the gil for the Alexandrite before there's enough Alexandrite on the market for me to buy, let alone before I finish any of those other things.
http://www.bluegartr.com/threads/907...=1#post4666916